Laws banning diesel vehicles from city centers are becoming increasingly common around Europe but may not deliver the intended environmental benefits.
One may think that the sharp decline in sales of diesel cars since the Volkswagen AG emissions-cheating scandal would be a boon to both environmentalists campaigning to reduce harmful gases in the atmosphere and carmakers, which are under intense pressure to meet new European Union regulations.
That is not necessarily the case.
Diesel's market share in the U.K. plunged to 23% in 2019, having accounted for more than half of car sales from 2010-2015. It is a trend that has been broadly similar across Europe, prompting some large automakers like Toyota Motor Corp. and Honda Motor Co. Ltd. to axe almost their entire diesel passenger car offerings, and Volvo to switch its focus increasingly to hybrids.
But while consumers are ditching diesels in droves, the gasoline cars many are reverting typically emit 10%-15% more CO2 than the diesel variant of the same car, said Al Bedwell, chief global powertrain analyst at U.K.-based consultancy LMC Automotive.
At the same time, as new diesels grow cleaner, gasoline cars can no longer boast comparatively lower nitrogen oxide, or NOx, emissions — the heart and lung-damaging gas for which diesel has gotten such a bad rap since "dieselgate."
"I think diesel is a technology they have all got and something they can all use [to meet the targets]," Bedwell said. "Euro 6 diesel is as clean as gasoline and some are claiming zero or near-zero NOx and they are better on CO2."
Euro 6 is the exhaust emissions standard diesel vehicles must meet to be sold within the EU and is the sixth in a series of gradually decreasing permissible legal limits for various pollutants.
Diesel's downfall narrows automakers' options as they contemplate how to minimize or avoid EU fines starting this year for carmakers who fail to cut the CO2 tailpipe emissions of their cars by a specified average. At €95 per gram over the limit for every car sold, PA Consulting in a Jan. 14 report estimated that the fines could total as much as €14.5 billion for all manufacturers in 2021. That equates to a penalty of close to €1,000 on each of the roughly 15 million new cars sold in the EU every year.
Carmakers have been playing down the likelihood of large fines, touting forthcoming hybrids and electrics. Nonetheless, Fiat Chrysler Automobiles NV's agreement to pay Tesla Inc. a reported $2 billion to help it dilute its CO2 average by pooling their sales through 2023 as if they were one company for the EU's purposes, is indicative of the depth of automakers' concern.
The 2020 EU CO2 target represents a 21% cut to average emissions from new cars sold in the bloc versus 2018's figure of 120.4 grams per kilometer, according to the Copenhagen-based European Environment Agency. CO2 emissions from vehicles in Europe have in fact risen over the past two years, in large part thanks to the growing popularity of larger SUVs.
Although European governments for years promoted diesel as a more climate-friendly alternative to gasoline, this changed suddenly with the revelations of the dieselgate scandal and growing awareness of the harm to health caused by NOx at the center of the furor.
Emissions of NOx have since been slashed, but the reputational damage done is such that the diesel powerplant has become something of a spent bullet as a means of lowering cars' CO2 emissions.
"I think [diesel] is dead," David Bailey, professor of business economics at the U.K.'s Birmingham Business School, told the Autonews website. "Governments have turned against it and the industry has failed to get across a clear message about its cleanliness."
NOx levels remain above legal limits in dozens of cities across the EU, mainly due to the presence of older diesels that comply only with earlier "Euro" standards. While that situation persists, nuances like a subsequent sharp drop in emissions since the recent introduction of mandatory NOx-reducing systems promoting cleaner air, are now glossed over.
Perhaps the starkest example of this is in the U.K. city of Bristol, which is proposing to ban all diesel vehicles in an attempt to bring city center air quality back within legal limits. Some experts have dismissed the proposal, which is still to clear central government scrutiny, as absurd for keeping out even the newest, cleanest vehicles that pollute far less than some older gasoline cars that would still have free rein on Bristol's roads.
A new on-road testing component to emissions tests, supplementing the traditional rolling-road laboratory test, has achieved a further squeeze on diesel emissions after the discovery that many cars exceeded legal limits under conditions of on-road use meant manufacturers had to rework the engines.
Although entailing a significant cleanup on some cars that had already achieved Euro 6 certification, the pollution purge brought about by the road test's revelations may have gone unnoticed by regulators in places like Bristol, with the obscure new label created for them called "Euro 6 d-temp" instead of a label like Euro 7 that might have denoted the step-change in emissions more clearly.
It means there are cars with a Euro 6 certificate that emit NOx at several times the legal limit and others that emit barely any.
"Euro 6 has been rendered meaningless," said Nick Molden, founder and CEO of Emissions Analytics, which produces a database of emissions for individual vehicles and advocates tailoring restrictions and permissions on the basis of each car's performance rather than the broad Euro categories.
Molden explained that Bristol's ban on all cars in the category would dredge out the cleanest along with earlier Euro 6 cars whose high on-road emissions went undetected until that extra testing was introduced.
"If someone has just bought a £30,000 new diesel that actually only emits 20mg/km and it gets banned from Bristol, the effect on air quality will be negligible, the utility effect on the consumer will potentially be great and the residual values of these vehicles will fall, costing the consumer," Molden said.
When asked about the decision at a Financial Times (London) conference on the future of mobility in November 2018, Bristol Mayor Marvin Rees could not specify exactly why the proposed ban will include new diesels of the latest Euro 6 standard, beyond noting that a computer model had indicated this was necessary.
Bristol's plan, together with similarly restrictive measures proposed by other cities including London, Birmingham and York, are having an impact reaching all the way to carmakers as motorists become hesitant to buy car models they consider liable to eventually fall foul of increasingly restrictive regulations.
"Political and economic uncertainty, and confusing messages on clean air zones have taken their toll on buyer confidence, with demand for new cars at a six-year low," said Mike Hawes, chief executive of the U.K.'s Society of Motor Manufacturers and Traders, in a statement following the release of the latest annual registration figures.
The number of battery-electric vehicles on sale in the EU is expected to balloon from 2020 onward — until now, options have been largely limited to Nissan Motor Co. Ltd.'s Leaf, Renault SA's Zoe and Bayerische Motoren Werke AG's i3. Under the new EU emissions rules, each sale of an electric or hybrid car emitting less than 50g of CO2 per km will receive an inflated weighting known as a super credit, boosting their contribution to lowering a manufacturer's average.
But many new models that will generate these super credits, such as Volkswagen's all-electric ID range and the electric Peugeot SA 208, will carry a price tag approaching that of a premium gasoline sedan or SUV and are still months from launch.
The newest diesel vehicles could provide a cleaner alternative to gasoline and offer consumers better value for money than electric cars, at least in the ramp-up phase. But the prospect of a revival of this much maligned technology seems highly improbable.
" VW [dieselgate] was a nail in the coffin," said LMC's Bedwell. "It is a pity because I think it still has a role to play. Banning diesel is too much of a blunt instrument."